Police have arrested a 26-year-old man in Renton, West Dunbartonshire over the murder of Northern Irish policeman Ronan Kerr as a massive arms dump is found in province.

DETECTIVES investigating the murder of policeman Ronan Kerr in Northern Ireland have arrested a man in Scotland just a few hours after his funeral was held.

A 26-year-old man was arrested in Renton Main Street at 1.10pm today.

It is understood tha man is already being taken back to Northern Ireland for questioning.

PC Kerr was killed when a booby trap device exploded under his FordMondeo at his Omagh home, near Beragh, as he got in to go to work onSaturday.

The news of the arrest came as PSNI Assistant Chief Constable Drew Harris also revealed the details of a massive arms find at a police press conference in Belfast.

He said: "Detectives from Serious Crime Branch who are investigating Ronan's murder have made a significant discovery of arms and munitions - one of the most significant in recent years. It was made in Coalisland last night.

"Within the last two hours a man has been arrested in Dunbartonshire in Scotland in connection with the find of weapons at Coalisland.

"This 26-year-old suspect is being brought back to Northern Ireland for questioning.

He added: "The arms discovery was made in Coalisland last night and will form lines of inquiry into Ronan's murder and into dissident activity generally.

"The seizure was made in a garage unit on the Mountjoy Road.

"Inside the unit police officers uncovered a number of stolen vehicles and inside those vehicles a significant amount of arms and munitions.

"The haul included: four rifles, ammunition, timer power units, detonators, incendiary bombs, components for rocket launchers and other explosive devices, and a quantity of explosives, possibly Semtex.

"This investigation into Ronan's murder will continue in the coming days and weeks with the same determination and professionalism which resulted in last night's discovery.

"Everyone in our country is much safer today because these munitions have been taken out of circulation.

"They will now be forensically examined and provide new lines of inquiry for our investigators."

A spokeswoman for Strathclyde Police said: "Strathclyde Police can confirm that a 26-year-old male was arrested at approximately 1.10pm on Main Street, Renton, Dunbartonshire.

"This arrest was made by Strathclyde Police officers in relation to an ongoing investigation led by the Police Service of Northern Ireland."

Earlier today police officers and senior nationalist sporting officials shouldered the coffin of murdered Catholic constable Kerr at his funeral in an unprecedented show of unity.

President of the Gaelic Athletic Association Christy Cooney and Police Service of Northern Ireland (PSNI) members carried the remains to the Church of the Immaculate Conception in Beragh, Co Tyrone.

His killing, blamed on dissident republicans opposed to the peace process, has sparked unanimous cross-community condemnation.

The funeral procession was accompanied by unifying images that would have been unimaginable during the Troubles.

First Minister Peter Robinson is the first Democratic Unionist Party leader to attend a Catholic Mass while the presence of Sinn Fein Deputy First Minister Martin McGuinness at the funeral of a police officer also represents a striking break with the past.

The small Tyrone village ground to a halt as local schoolchildren and members of the officer's boyhood gaelic football club flanked the cortege led by his mother Nuala, who days ago appealed that his loss not be in vain.

Dave Cording, deputy chief executive at Crimestoppers, said: "A police officer who was willing to stand up and serve his community has had his life tragically cut short.

"This was a despicable crime. For that reason, a reward of up to s50,000 is being offered to anyone who can supply us with information leading to the arrest and conviction of the person or persons responsible."

Robinson condemned the killing when he addressed business leaders in Belfast.

He said: "This was an utterly futile act designed to divide and destroy."

Thousands of people are expected to gather in Belfast at a trade union-organised peace rally to protest at the killing.